Identification of Cl and Na impurities in inclusions of a vapor-grown CdTe doped with Zn and Cl

Morphology and analysis of composition of inclusions were done by secondary electron microscopy and spatially resolved energy-dispersive analysis of x-ray on semiintrinsic CdTc:Cl and CdTe:Zn:Cl crystals grown from the vapor phase by the modified Markov technique and on undoped CdTc crystals grown from the melt by the Bridgman method. In CdTe:Cl and CdTe:Zn:Cl crystals nonstoichiometric inclusions of about 10-20 mum were found, which contain high concentrations of Cl and Na impurities. The Cl is concentrated in small precipitates of 1-2 mum inside these inclusions. After short-time low-temperature annealing (600 degreesC), the inclusions mostly disappeared.